Expression of COX-2 and transcription factor CCAAT enhancer binding proteinβin refractory sinusitis with nasal polyps and its significance

Objective To study the expression and significance of COX-2 and C/EBP-βin refractory sinusitis with nasal polyps,and to explore the relationship between them and the recurrence of sinusitis with nasal polyps.Methods The protein expression of COX-2 and C/EBP-βin 20 cases of refractory sinusitis with nasal polyps,20 cases of sinusitis with nasal polyps and 20 cases of normal nasal mucosa were detected by western blot,and the relationship between the two was compared.Results The expression levels of COX-2 and C/EBP-βin refractory sinusitis with nasal polyps were significantly different from those in refractory sinusitis with nasal polyps(P<0.05);The expression levels of COX-2 and C/EBP-βin sinusitis tissues with nasal polyps were significantly different from those in normal nasal mucosa tissues(P<0.05);The expression levels of COX-2 and C/EBP-βin each group were significantly correlated(P<0.05).Conclusions The high expression of COX-2 and C/EBP-βmay be closely related to postoperative recurrence of sinusitis patients with nasal polyps.Both may be used as objective indicators to judge the postoperative follow-up and recurrence tendency of patients with sinusitis with nasal polyps..

IMMUNOHISTOCHEMICAL DEMONSTRATION OF CCAAT/ENHANCER BINDING PROTEIN (C/EBP) IN HUMAN LIVER TISSUES OF VARIOUS ORIGIN

C / EBP is a sequence-specific DNA-binding protein. In order to indentify its distribution and localization, immunohistochemical technique (ABC method) was done using anti-C / EBP polypeptide antibodies 1103#, 425# in liver specimens from 20 normal adults, 5 neonates, 6 patients with hepatitis, 25 with liver cirrhosis, 80 with hepatocellular carcinoma (40 cases were associated with surrounding nontumorous tissues) and 26 patients with cholangiocarcinoma (15 cases were associated with surrounding nontumorous tissues). The results showed that C / EBP was diffusely distributed in nuclei and cytoplasm of differentiated liver cells and very low or undetectable in liver cancer cells. The manifestation of C / EBP correlated with degree of differentiation of tumour cells, and was obviously weaker than that in surrounding nontumorous tussues. C / EBP positive staining has also been found in regenerating epithelial cells of bile ductules. The results suggested that C / EBP should play an important role in establishing and maintaining the differentiation of liver cells.

Saikosaponin D inhibits proliferation and induces apoptosis via C/EBPβ-p53 signal pathway in human hepatoma HepG2 cells

Objective To investigate the anticancer effects and detailed mechanisms of Saikosaponin D(SSD)in human hepatoma HepG2 cells.Methods Cell proliferation and apoptosis were tested by MTT assay and Annexin-V/PI assay respectively.The expressions of CCAAT enhancer binding protein β(C/EBPβ)and p53 were detected by RT-PCR and Western blotting.Results SSD inhibited cell proliferation in a dose-dependent manner and induced apoptosis at the concentration of 5.0 mg/L.SSD significantly increased the mRNA and protein levels of C/EBPβ and p53 in a dose-dependent manner.Conclusion SSD exerts its anticancer effect by inhibiting cell proliferation and inducing apoptosis partly through C/EBPβ-p53 signal pathway in HepG2 cells.

Celecoxib attenuates hepatocyte apoptosis by inhibiting endoplasmic reticulum stress in thioacetamide-induced cirrhotic rats

BACKGROUND Endoplasmic reticulum(ER)stress is an important mechanism in the progression of chronic and acute liver diseases,especially in the progression and recovery of liver fibrosis.Excessive and long-term ER stress induces apoptosis.ER stressinduced apoptosis is considered to be an important pathway in the development of liver fibrosis.Cyclooxygenase-2(COX-2)induction is also closely related to ER stress.In our previous studies,we showed that celecoxib,a COX-2 inhibitor,improves liver fibrosis and portal hypertension.However,the role and mechanism of celecoxib in alleviating liver fibrosis remain unclear.AIM To investigate whether celecoxib alleviates liver fibrosis by inhibiting hepatocyte apoptosis via the ER stress response.METHODS Cirrhosis was induced by intraperitoneal injections of thioacetamide(TAA)for 16 wk(injection dose is 200 mg/kg per 3 d for the first 8 wk and 100 mg/kg per 3 d after 8 wk).Thirty-six male Sprague-Dawley rats were randomly divided into three groups,namely,control group,TAA group,and TAA+celecoxib group.In the last 8 wk,TAA-induced cirrhotic rats received celecoxib(20 mg/kg/day)or the vehicle by gastric gavage.After 16 wk,the rats were sacrificed,and serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),and albumin(ALB)were detected.The hepatic fibrosis areas were evaluated by Sirius red staining and the degree of fibrosis was assessed by measuring the level of hydroxyproline.ER stress levels were evaluated by detecting the marker proteins glucose-regulated protein 78(GRP78),CCAAT/enhancer binding protein homologous protein(CHOP),PKR-like ER protein kinase(PERK),activating transcription factor 6(ATF6),and inositol-requiring enzyme 1 alpha(IRE1α).Apoptosis levels were evaluated by detecting caspase-12 and caspase-3.RESULTS The serum ALT and AST levels in the liver were significantly reduced by celecoxib;however,the serum ALB had no significant changes.Celecoxib significantly reduced the degree of liver fibrosis and the levels of hydroxyproline(-38%and-25.7%,respectively,P<0.01).Celecoxib ameliorated ER stress by reducing the level of GRP78 compared to the TAA group(P<0.05).Consistently,after celecoxib administration,the upregulation of TAA-induced hepatic apoptosis markers(caspase-12 and caspase-3)and CHOP were significantly inhibited.In addition,after celecoxib treatment,the expression of key molecules associated with ER stress(PERK,ATF6,and IRE1)was decreased(P<0.05).CONCLUSION Therapeutic administration of celecoxib effectively reduces hepatic apoptosis in TAA-induced cirrhotic rats.The mechanism of action may be attributed to the suppression of CHOP expression,which subsequently inhibits ER stress.

Transcription factor changes following long term cerebral ischemia/reperfusion injury

The present study established a rat model of cerebral ischemia/reperfusion injury using four-vessel occlusion and found that hippocampal CA1 neuronal morphology was damaged, and that there were reductions in hippocampal neuron number and DNA-binding activity of cAMP response element binding protein and CCAAT/enhancer binding protein, accompanied by decreased learning and memory ability. These findings indicate that decline of hippocampal cAMP response element binding protein and CCAAT/enhancer binding protein DNA-binding activities may contribute to neuronal injury and learning and memory ability reduction induced by cerebral ischemia/reperfusion injury.

Edaravone protects against oxygen-glucose-serum deprivation/restoration-induced apoptosis in spinal cord astrocytes by inhibiting integrated stress response

We previously found that oxygen-glucose-serum deprivation/restoration（OGSD/R） induces apoptosis of spinal cord astrocytes, possibly via caspase-12 and the integrated stress response, which involves protein kinase R-like endoplasmic reticulum kinase（PERK）, eukaryotic initiation factor 2-alpha（eIF2α） and activating transcription factor 4（ATF4）. We hypothesized that edaravone, a low molecular weight, lipophilic free radical scavenger, would reduce OGSD/R-induced apoptosis of spinal cord astrocytes. To test this, we established primary cultures of rat astrocytes, and exposed them to 8 hours/6 hours of OGSD/R with or without edaravone（0.1, 1, 10, 100 μM） treatment. We found that 100 μM of edaravone significantly suppressed astrocyte apoptosis and inhibited the release of reactive oxygen species. It also inhibited the activation of caspase-12 and caspase-3, and reduced the expression of homologous CCAAT/enhancer binding protein, phosphorylated（p）-PERK, p-eIF2α, and ATF4. These results point to a new use of an established drug in the prevention of OGSD/R-mediated spinal cord astrocyte apoptosis via the integrated stress response.

Tetratricopeptide repeat domain 36 deficiency mitigates renal tubular injury by inhibiting TGF-β1-induced epithelialemesenchymal transition in a mouse model of chronic kidney disease

The damage of proximal tubular epithelial cells(PTECs)is considered a central event in the pathogenesis of chronic kidney disease(CKD)and deregulated repair processes of PTECs result in epithelialemesenchymal transition(EMT),which in turn aggravates tubular injury and kidney fibrosis.In this study,we firstly revealed that the reduction of TTC36 is associated with unilateral ureteral obstruction(UUO)-induced CKD;besides,ablation of TTC36 attenuated tubular injury and subsequent EMT in UUO-treated mice kidneys.Consistently,TTC36 overexpression promoted EMT in TGF-β1-induced HK2 cells.Moreover,TTC36 elevated the protein expression of CEBPB,which was involved in the regulation of TGF-β/SMAD3 signaling,and augmented SMAD3 signaling and downstream genetic response were reduced by CEBPB silencing.Collectively,our results uncovered that TTC36 deficiency plays a protective role in tubular injury and renal fibrosis triggered by UUO;further,TTC36 overexpression exacerbated TGF-β/SMAD3 signaling via elevating the stability of SMAD3 and CEBPB,suggesting that TTC36 inhibition may be a potential strategy in the therapy of obstructive nephropathy.

Identification and validation of novel C/EBPp-regulated genes in preadipocyte proliferation

Background CCAAT/enhancer-binding protein β（C/EBPβ） is required for mitotic clonal expansion （MCE） during adipogenesis. It is still unclear how C/EBPp regulates MCE in the earlier differentiation programs of 3T3-L1 preadipocytes. The purpose of this paper was to understand why C/EBPβ is required for preadipocyte proliferation, and identify new target genes of C/EBPP with chromatin immunoprecipitation （ChlP）-on-chip. Methods Postconfluent growth-arrested 3T3-L1 preadipocytes were induced to differentiation using a standard differentiation protocol. Chip was performed at 20 hours after induction with specific anti-C/EBPβ antibodies. The precipitated DNA was amplified, labeled and hybridized with a mouse promoter microarray. Compared with the control in which the ChIP experiment was performed with non-specific antibody, only the genes with a signal increasing more than 2 fold were considered as candidate genes.Results A total of 110 candidate genes were identified. BTG3 associated nuclear protein （SMAR1, Banp） and tripartite motif-containing 35 （Hls5, trim35） were two target genes among the 110 candidate genes which are involved in cell cycle regulation; the binding of C/EBP3 to the promoter of banp and trim35 was verified by ChlP-PCR. Conclusion C/EBPβ may regulate preadipocyte proliferation through activation of banp and trim35.